The first-order RC circuit can be used to perform a lowpass or highpass filtering operation.

听力原文： Mass media are tools of communication. Mass media allow us to record and pass information rapidly to a large, scattered audience. They extend our ability to talk to each other by helping us overcome barriers caused by time and space. There are various ways in which mass media make daily life easier for us. First, they inform. and help us keep a watch on our world. They gather and pass on information we would be unlikely or unable to obtain on our own. Second, mass media help us to arrange our time and life. What we talk about and what we think about are greatly influenced by the media. When people get together, they tend to talk about certain happenings in the newspapers or on TV. Because we are exposed to differing points of view through different kinds of media every day, we are able to evaluate all sides of a certain issue. Third, the media are used to persuade people. A good example is advertisements through the media. Newspapers, magazines and TV are filled with all kinds of colorful, persuasive advertisements. Though many advertisements may not say openly that they want you to buy a certain product, they describe their products in such a way that you may want to buy them. Fourth, the media also entertain. All of the media make some effort to try to entertain their audience. For instance, even though the newspaper is primarily a medium of information, it also contains entertainment features. Television, motion pictures, fiction hooks and some radio stations and magazines are devoted mainly to entertainment. It is estimated that in the future, the entertainment function of mass media will become even more important than it is now.

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A．To make people well informed about the world.

B．To amuse and entertain people.

C．To help people arrange their time and life.

D．To give people a sense of honor.

An assumption is something taken for granted. Everyone makes assumptions--you have to in order to say anything. As a critical reader, you need to determine what the assumption is and then decide whether you agree or disagree with the assumption. Once you decide, your attitude toward the argument will change. Careful, honest writers know what their assumptions are and lay the most important ones out for all to judge. Hidden assumptions may be all right for humor or fairly harmless in topical journalism, but they can be dangerous in serious written argument. Important assumptions should be explicit and detailed, for then the reader can judge their validity. If you do not agree with a writer's assumptions, then you will never agree with his/her arguments,

As indicated above, an assumption is a belief that we take for granted as a basis for an assertion, All kinds of statements rely on assumptions--questions, commands, promises, and assertions. The simple command "Pass the salt" is based on several assumptions, including that the salt can be passed, that you can pass it, and that I have the right to ask you to pass it. Some assumptions are unexpressed. We would be the joke of the neighbourhood if we went around articulating our assumptions every time we asked someone to pass the salt. We get into trouble, however, when we fail to recognize important assumptions that subtly guide our thoughts. Sophocles said, "Reason is God's crowning gift to man." A statement like this seems innocent enough. When we think about it, we easily recognize that he was basing the statement on two major assumptions: (1) that man has a mind, and (2) that God exists. Hidden in the statement, however, are some subtle assumptions that we may or may not support, including; (1) God is a personal force capable of making a gift; (2) reason is a more important gift than heart, soul, or body; and (3) woman's mind is not a gift of God. Once we articulate these assumptions, we might disagree. (339)

According to this passage, an assumption is ______.

A．something that everyone knows

B．the idea the writer wants to emphasize

C．the reader's knowledge about the topic

D．foundation of the writer's reasoning

An assumption is something taken for granted. Everyone makes assumptions--you have to in order to say anything. As a critical reader, you need to determine what the assumption is and then decide whether you agree or disagree with the assumption. Once you decide, your attitude toward the argument will change. Careful, honest writers know what their assumptions are and lay the most important ones out for all to judge. Hidden assumptions may be all right for humor or fairly harmless in topical journalism, but they can be dangerous in serious written argument. Important assumptions should be explicit and detailed, for then the reader can judge their validity. If you do not agree with a writer's assumptions, then you will never agree with his/her arguments.

As indicated above, an assumption is a belief that we take for granted as a basis for an assertion. All kinds of statements rely on assumptions--questions, commands, promises, and assertions. The simple command "Pass the salt" is based on several assumptions, including that the salt can be passed, that you can pass it, and that I have the right to ask you to pass it. Some assumptions are unexpressed. We would be the joke of the neighbourhood if we went around articulating our assumptions every time we asked someone to pass the salt. We get into trouble, however, when we fail to recognize important assumptions that subtly guide our thoughts. Sophocles said, "Reason is God's crowning gift to man. "A statement like this seems innocent enough. When we think about it, we easily recognize that he was basing the statement on two major assumptions: (1) that man has a mind, and (2) that God exists. Hidden in the statement, however, are some subtle assumptions that we may or may not support, including: (1) God is a personal force capable of making a gift; (2) reason is a more important gift than heart, soul, or body; and (3) woman's mind is not a gift of God. Once we articulate these assumptions, we might disagree.

According to this passage, an assumption is ______.

A．something that everyone knows

B．the idea the writer wants to emphasize

C．the reader's knowledge about the topic

D．foundation of the writer's reasoning

Drivers on the Basingstoke by-pass used to have their attention diverted by a sign that reads A MOMENT'S INATTENTION CAUSES ACCIDENTS. This self-defeating warning has now been removed, but its message is still very much to the point.

Almost anything can cause an accident. Apart from momentary inattention, it might be a minor miscalculation, a sudden fit of coughing, a bop on the head with a teddy-bear from a child in the back seat, an argument with the wife, fog, falling asleep at the wheel, bad eyesight, a glaring sun, ice, rain, wind, or snow-all these can make the difference between a tragic hit and a lucky miss.

Although human error plays its part, it is by no means the only cause of accidents. There must be some cause other than simple human error. Road construction plays its part: researchers have found that it is not at the obvious danger spot- sharp corners, cross-roads, narrow lanes — that accidents happen. It is on those roads where there are subtle visual traps, unexpected changes in the shape or surface of the road, or even insufficient or badly-placed signs. Wherever there is a "black spot", it means that something is seriously wrong with the road. Why else did the careless driving of so many come out at that particular spot?

What the law requires when you have an accident.

There are, firstly the legal formalities of exchanging names and addresses with others involved in an accident and, in Certain cases, informing the police. However, you are required by law to stop after an accident only if.

1. Somebody other than yourself in or outside your car has been injured.

2. A vehicle not of your own has been damaged.

3. Any horse, cow, donkey, sheep, or dog has been injured.

It has been said that if a driver continues unaware of causing injury he must be acquitted. But the courts are wary of that excuse. Furthermore, the driver himself must wait at the scene; it is not enough for him to leave his chauffeur or a friend to attend to the boring formalities while he goes off on more important business.

If you have been involved in an accident and have stopped, you must give your name, address, and registration number to anyone who has a good reason for requesting it; this means anyone affected by the accident. If these formalities which are complied with it is not necessary to wait for the arrival of the police. It is, however, often wise to do so. The police are experts at drawing plans, taking measurements and photographs and gathering other evidence. In your absence the police could be given a biased story against you; and you yourself might warn to point out certain features of the accident to the police.

A MOMENT'S INATTENTION CAUSES ACCIDENTS (para. 1) is a self-defeating warning because ______ .

A．it will make a driver wait at the scene

B．it will distract the driver's attention

C．it is too difficult to understand

D．it is too long to be read by drivers

Drivers on the Basingstoke by-pass used to have their attention diverted by a sign that reads A MOMENT'S INATTENTION CAUSES ACCIDENTS. This self-defeating warning has now been removed, but its message is still very much to the point.

Almost anything can cause an accident. Apart from momentary inattention, it might be a minor miscalculation, a sudden fit of coughing, a bop on the head with a teddy-bear from a child in the back seat, an argument with the wife, fog, falling asleep at the wheel, bad eyesight, a glaring sun, ice, rain, wind, or snow-all these can make the difference between a tragic hit and a lucky miss.

Although human error plays its part, it is by no means the only cause of accidents. There must be some cause other than simple human error. Road construction plays its part: researchers have found that it is not at the obvious danger spot- sharp corners, cross-roads, narrow lanes — that accidents happen. It is on those roads where there are subtle visual traps, unexpected changes in the shape or surface of the road, or even insufficient or badly-placed signs. Wherever there is a "black spot", it means that something is seriously wrong with the road. Why else did the careless driving of so many come out at that particular spot?

What the law requires when you have an accident.

There are, firstly the legal formalities of exchanging names and addresses with others involved in an accident and, in Certain cases, informing the police. However, you are required by law to stop after an accident only if.

1. Somebody other than yourself in or outside your car has been injured.

2. A vehicle not of your own has been damaged.

3. Any horse, cow, donkey, sheep, or dog has been injured.

It has been said that if a driver continues unaware of causing injury he must be acquitted. But the courts are wary of that excuse. Furthermore, the driver himself must wait at the scene; it is not enough for him to leave his chauffeur or a friend to attend to the boring formalities while he goes off on more important business.

If you have been involved in an accident and have stopped, you must give your name, address, and registration number to anyone who has a good reason for requesting it; this means anyone affected by the accident. If these formalities which are complied with it is not necessary to wait for the arrival of the police. It is, however, often wise to do so. The police are experts at drawing plans, taking measurements and photographs and gathering other evidence. In your absence the police could be given a biased story against you; and you yourself might warn to point out certain features of the accident to the police.

A MOMENT'S INATTENTION CAUSES ACCIDENTS (para. 1) is a self-defeating warning because ______ .

A．it will make a driver wait at the scene

B．it will distract the driver's attention

C．it is too difficult to understand

D．it is too long to be read by drivers

Drivers on the Basingstoke by-pass used to have their attention diverted by a sign that read-A MOMENT'S INATTENTION CAUSES ACCIDENTS. This self-defeating warning has now been removed but its message is still very much to the point. Almost anything can cause an accident. Apart from momentary inattention, it might be a minor miscalculation. Although human error plays its part, it is by no means the only cause of accidents. There must be some causes other than simple human error. Road construction also plays its part. It is on those roads where there arc subtle visual traps. Wherever there is a "black spot", it means that something is seriously wrong with the road.

If you have been involved in an accident and have been stopped, you must give your name, address, and registration number to anyone who has a good reason for requesting it; this means anyone affected by the accidents. If somebody is injured, the driver must produce his insurance certificate on request. If these formalities are complied with it is not necessary to wait for the arrival of the police. It is, however, often wise to do so. The police are expert at drawing plans, taking measurements and photographs and gathering other evidence. In your absence the police could be given a biased story against you; and you yourself might want to point out certain features of the accident to the police.

A MOMENT'S INATTENTION CAUSES ACCIDENTS is a self-defeating warning because______.

A．it is not tree

B．it will distract the driver's attention

C．it is too difficult to understand

D．it is too long to be read while driving a car